Many utility vehicles have a front-rear two-row seat configuration composed of a front seat and a back seat or a single-row seat configuration. Furthermore, a cargo bed (cargo) is provided rearward of the seats. With a convertible cargo, the space of the seats can be used as expansion space for the cargo. For example, with the utility vehicle disclosed in U.S. Pat. No. 8,322,772, a seat back included in a rear seat is attached so as to be able to swing between an upright position at which the rear surface thereof is an approximately vertical plane, and a lowered position at which the rear surface is an approximately horizontal plane. The front surface of the seat back in the lowered position overlaps with the seat bottom. If a heavy object is placed in the expansion area of the cargo floor created on the seat back that has been swung to the lowered position, there is a possibility that the seat back will strongly press against the seat bottom. Also, with this structure, the flatness of the floor of the expanded cargo is not necessarily ensured.
With the utility vehicle disclosed in U.S. Pat. No. 8,075,040, the seat back and seat bottom of the rear seat are separate and are constituted by separate members. The seat back is attached to the rear surface of the front floor, which can swing to a horizontal orientation and an upright orientation. The front floor in the horizontal orientation forms a portion of a bed floor of a utility bed (cargo) and the front floor in the upright orientation functions as a support frame for the seat back. The seat bottom is attached to the bottom surface of the front wall of the utility bed. The front wall can also swing to the upright orientation and the horizontal orientation, and the front floor in the horizontal orientation functions as a support frame for the seat bottom. With this rear seat structure, when the rear seat is folded to expand the space of the cargo, the seat backs are separate and do not overlap. However, the structure is complicated and the manufacturing cost is a problem. Furthermore, since a structure is used in which the seat backs are completely separate, it is difficult to correct the positional relationship between the seat backs. As a result, the seat comfort deteriorates.